[LLVMdev] How to call native functions from bytecode run in JIT?

[Jan Rehders]

Hi,

> Okay.  If the function exists in your application's address space  
> already,
> just name the LLVM function the same name as the native function  
> and the
> JIT should find it an do the right thing.  This is how it finds  
> printf and
> a variety of other things.  You don't need to call addGlobalMapping at
> all.

Looking at the output of "nm codegen1" I realized that "get5" was a C+ 
+ function whose name was mangled to "__Z4get5v". Surrounding it by  
extern "C" helped a lot :) Now the function is found by the JIT and I  
can call it using EE->runFunction als well as using a CallInst.

> Does this work?

However, one strange effet remains: if I first call the function  
using EE->runFunction and then try to call it using a CallInst inside  
another function I get the old "relocation" error in PPCJITInfo.cpp,  
again. Using a CallInst first, then runFunction and then a CallInst  
again works, though. For my project this is probably a non-issue but  
it might indicate some problem in either my code or LLVM - any ideas?

Anyway, thank you all for the helpful comments. I'd surely yielded to  
despair without your help :)

- Jan